In an application field with relatively high reliability requirements, when a host routing engine configured on a network device becomes abnormal or breaks down, a Graceful Restart (GR) function is used to ensure uninterrupted traffic forwarding. Two kinds of network devices, i.e. a GR Restarter and a GR Helper, used in the GR process are defined in the GR protocol. A failed network device which is restarted is called the GR Restarter, and a neighbor network device of the GR Restarter is called a GR Helper. The GR Restarter executes the GR function with the help of the GR Helper.
When a network device is restarted, the network device acting as the GR Restarter sends an open packet to all neighbor network devices acting as the GR Helpers to re-establish a connection, and performs route selection after receiving routes sent from all the neighbor network devices.